JP2003-205808 A discloses a parking assist apparatus which includes torque-up means for increasing engine generating torque by a predetermined torque when an accelerator pedal is off in order to enlarge a control range of vehicle speed based on only the brake operation. According to this parking assist apparatus, when a driver presses down on the brake pedal and operates a shift lever to a reverse position, an instruction for performing torque-up of the engine is transmitted to an engine ECU from a parking assist ECU.
By the way, when a step exists in a path along which reverse traveling is planed, there may be a case where the vehicle cannot surmount the step even if maximum torque in a brake-off status is generated.
Regarding this, since the parking assist apparatus disclosed in JP2003-205808 A has the torque-up means for increasing engine generating torque at the time of accelerator pedal-off by a predetermined torque, it may be possible to avoid a situation in which the vehicle cannot surmount the step if the engine generating torque at the time of accelerator pedal off is increased up to such torque which enables the vehicle to surmount the step. With such an arrangement, convenience is increased under road situations with steps; however, convenience is conversely diminished under flat road situations, because under the flat road situations an increase in vehicle speed at the time of accelerator pedal off is promoted and thus the parking assist may be terminated due to an upper limit of the vehicle speed or the driver may become restless due to the unpredicted increase in vehicle speed.